Phosphate Ions Research Articles

Research on the production of sorbent based on bentonite clay for wastewater treatment from chemical industries

In our country, the problem of water purification remains urgent, with the growth of external factors contributing to this, which can include an increase in the number of industrial enterprises, the development of agriculture, urban growth and others. To solve the problem of water purification it is economically advantageous to create new sorbents, with the available resources in our country.For the processing of of bentonite clay under experimental conditions, instrumental test methods were chosen using a scanning electron microscope (SEM) of the Jeol JSM-6490l V brand, a multi-parameter portable cyberscanner (PCD 650 Eutech) and a Q-1500 Derivatograph. In this article, we studied the bentonite of the Darbaza deposit. For physico-chemical analysis of clay from the Darbaza deposit, a specially selected sample was crushed, and sieved and its chemical composition was determined. Results. Based on the results of instrumental studies, the elemental and mineralogical composition of bentonite clay from the Darbazinsky deposit was determined using a scanning electron microscope JSM-6490l V (Jeol, Japan) using the energy-dispersive method. The resulting sorbent based on bentonite clay has a high sorption capacity and is recommended for use in the treatment of wastewater from chemical industries. The resulting sorbent based on bentonite clay from the Darbaza deposit makes it possible to purify wastewater from phosphate production from phosphate and other ions up to 60%. The developed sorbent based on bentonite clay has environmental and economic efficiency and connections with the use of local natural resources. Thus, it should be noted that for adsorption treatment of wastewater from chemical industries with a high degree, it is possible to use effective sorbents based on bentonine clays from the Darbaza deposit. It should also be noted that the use of bentonite clays for water purification by the sorption process is an effective and affordable alternative to adsorbents that show high adsorption capacity for various compounds.

Correction to: The Influence of Phosphate Ion Concentrations on the Properties of Wollastonite-Apatite-Based Cements

Correction to: The Influence of Phosphate Ion Concentrations on the Properties of Wollastonite-Apatite-Based Cements

Smartphone assisted paper strip-based colorimetric sensing of phosphate and copper ions utilizing bi-ligand intercalated cobalt-MOF as a dual functional nanozyme

Monitoring phosphate and copper ions is vital for environmental and food safety due to associated health risks. To address this need, a new cobalt and bi-organic ligand based metal organic framework (BDC-Co-BIm MOF) has been developed. This MOF acts as a dual-function nanozyme, displaying peroxidase-like activity and selective detection abilities for PO43- ion. The Co(II) nodes and sp2 carbon within the framework exhibit excellent Fenton-like reaction, efficiently catalyzing the conversion of 3,3′,5,5′-tetramethylbenzidine (TMB) into oxidised TMB (oxTMB). Also, steady-state kinetic analysis indicated that BDC-Co-BIm MOF exhibited high affinity toward both TMB and H2O2. The Co(II) nodes and positive charge of the BDC-Co-BIm MOF capture PO43- ion through Co-O-P bonding and electrostatic interaction, limiting the electron transfer between BDC-Co-BIm MOF and H2O2. This reduces TMB oxidation and changes the color from blue to colorless. When ionic Cu2+ ion are added to the system, they react with PO43- ion to form a stable Cu3(PO4)2 complex. This reactivates the electron transfer process, allowing the H2O2 to decompose into •OH. As a result, TMB oxidation is restored and producing the blue color product again. Based on these principles, a colorimetric assay has been developed for the rapid and selective detection of PO43- and Cu2+ ions. A strong linear correlation has been established between their concentrations and the UV absorbance at 652 nm, with limit of detection (LOD) of PO43- and Cu2+ was 0.05 and 0.13 µM, respectively. These limits are notably lower than the thresholds established by the Environmental Protection Agency and World Health Organization (EPA & WHO) at 0.18 µM for PO43- and 30 µM for Cu2+. A Paper-based smartphone-assisted sensing of PO43- and Cu2+ ions was successfully achieved using intelligent Red, Green, and Blue (RGB) analysis. The platform showed high selectivity and performance with environmental water samples. This research presents a novel method for visually detecting PO43- and Cu2+ ions using versatile nanozyme, advancing portable on-site environmental safety analysis.

Hydroxyapatite Film with Distinctive Roughness for Simulating the Bone Microenvironment and Revealing the Behavior of Metastatic Mammary Cancer.

Breast cancer is a common malignant tumor arising in normal mammary epithelial tissues. Nearly 75% of the patients with advanced mammary cancer develop bone metastases, resulting in secondary tumor growth, osteolytic bone degradation, and poor prognosis. The bone matrix comprises a highly hierarchical architecture and is composed of a nonmineral organic part, a predominantly type-I collagen, and a mineral inorganic part composed of hydroxyapatite (HA) nanocrystals (Ca10(PO4)6(OH)2). Although there has been extensive research indicating that the material properties of bone minerals affect metastatic breast cancer, it remains unclear how the microenvironment of the bone matrix, such as the roughness, which changes as a result of osteolytic bone remodeling, affects this disease. In this study, we created HA coatings in situ on polyelectrolyte multilayers (PEMs) by incubating PEMs in a mixture of phosphate and calcium ions. The HA films with distinctive roughness were successfully collected by controlling the incubation time, which served as the simulated microenvironment of the bone matrix. MDA-MB231 breast cancer cells were cultured on HA films, and an optimal roughness was observed in the adhesion, proliferation, and expression of two cytokines closely related to bone metastasis. This study contributed to the understanding of the effect of the microenvironment of the bone matrix, such as the roughness, on the metastasis behavior of breast cancer.

U(VI) mitigation via forward osmosis: Elucidation of retention mechanisms and co-ion effects

Uranium (U) is a chemical and radioactive toxic contaminant affecting many groundwater systems. The focus of this study was to evaluate the suitability of forward osmosis (FO) for uranium rejection from contaminated groundwater under field-relevant conditions. Laboratory experiments with aqueous solution containing uranium were performed with FO membrane to understand the uranium rejection mechanism under varied pH, draw solution concentration, and presence of co-ions. Further, experiments were performed with U-contaminated field groundwater. Results of the hydrogeochemcial modelling using PHREEQC indicated that the rejection mechanism of uranium was highly dependent on aqueous speciation. Uranium rejection was maximum at alkaline pH with ca. 99% rejection due to charge-based interactions between membrane and dominant uranyl complexes. The results of the co-ion study indicated that nitrate and phosphate ions decrease uranium rejection. Whereas, bicarbonates, calcium, and magnesium ions concentrated uranium in feed solution. Further, the uranium adsorption onto the membrane surface primarily depended on pH of the aqueous solution with maximum adsorption at pH 5.5. Our results show that the World Health Organization's drinking water guideline value of 30 μgL−1 for U could be achieved via FO process in field groundwater containing low dissolved solids.

Characteristics of Phosphate Sorption on Surface Sediments: A Study in Kendari Bay

Phosphate adsorption and desorption are significant processes that influence the presence of phosphate in aquatic ecosystems and regulate the concentration of phosphate at the water-sediment interface. This research aims to investigate the characteristics of phosphate adsorption and desorption in Kendari Bay sediments, study the relationship between adsorption capacity and sediment characteristics and its phosphorus fraction, and evaluate its potential contribution to the overlying water column. Physicochemical measurements of the water and sediments were performed in the sampling location and the laboratory. Two types of adsorption-desorption kinetics models and two types of isothermal adsorption models were used to estimate the adsorption rate and capacity of the surface sediments. Adsorption kinetics and desorption kinetics experiments produced pseudo-second-order kinetic model equations with regression coefficients (R2) of 0.865–0.936 and 0.886–0.947, respectively. The isothermal adsorption experiment follows the Langmuir equation model with R2 = 0.964. The maximum adsorption capacity (Qmax) value was 156.3–227.3 mg/kg, and the phosphate concentration value at zero equilibrium (EPC0) was 0.0026–0.0047 mgP/L. Notably, the EPC0 value was higher than the SRP concentration, indicating that the resuspension of phosphate ions from sediment into the water column could occur. Furthermore, there was a correlation between Qmax values with OP, Al-P, Fe-P, clay particles, and organic materials. Potential practical applications may include integrating sediment adsorption capacity data into ecosystem models to inform nutrient management strategies and promote sustainable coastal development in Kendari Bay and beyond.

New Zein Protein Composites with High Performance in Phosphate Removal, Intrinsic Antibacterial, and Drug Delivery Capabilities.

Herein, poly(N-(4-aminophenyl)methacrylamide)-carbon nano-onions [abbreviated as PAPMA-CNOs (f-CNOs)] integrated gallic acid cross-linked zein composite fibers (ZG/f-CNOs) were developed for the removal/recovery of phosphate from wastewater along with controlled drug delivery and intrinsic antibacterial characteristics. The composite fibers were produced by Forcespinning followed by a heat-pressure technique. The obtained ZG/f-CNOs composite fibers presented several favorable characteristics of nanoadsorbents and drug carriers. The composite fibers exhibited excellent adsorption capabilities for phosphate ions. The adsorption assessment demonstrated that composite fibers process highly selective sequestration of phosphate ions from polluted water, even in the presence of competing anions. The ZG/f-CNOs composite fibers presented a maximum phosphate adsorption capacity (qmax) of 2500 mg/g at pH 7.0. This represents the most efficient phosphate adsorption system among all of the reported nanocomposites to date. The isotherm studies and adsorption kinetics of the adsorbent showed that the adsorption experiments followed the pseudo-second-order and Langmuir isotherm model (R2 = 0.9999). After 13 adsorption/desorption cycles, the adsorbent could still maintain its adsorption efficiency of 96-98% at pH 7.0 while maintaining stability under thermal and chemical conditions. The results mark significant progress in the design of composite fibers for removing phosphates from wastewater, potentially aiding in alleviating eutrophication effects. Owing to the f-CNOs incorporation, ZG/f-CNOs composite fibers exhibited controlled drug delivery. An antibiotic azithromycin drug-encapsulated composite fibers presented a pH-mediated drug release in a controlled manner over 18 days. Furthermore, the composite fibers displayed excellent antibacterial efficiency against Gram-positive and Gram-negative bacteria without causing resistance. In addition, zein composite fibers showed augmented mechanical properties due to the presence of f-CNOs within the zein matrix. Nonetheless, the robust zein composite fibers with inherent stimuli-responsive drug delivery, antibacterial properties, and phosphate adsorption properties can be considered promising multifunctional composites for biomedical applications and environmental remediation.

Benzidine-based chemosensors for the selective detection of phosphate, carbonate and copper ions: Applications in water and food sample analysis and on-field detection kit

In this work, benzidine-based chemosensors were synthesized. A5R1 had a cage-like structure along with 2-OH binding sites for encapsulation of Cu2+, A5R2 was found to bind with PO43¯ and CO32¯ ion; whereas A5R3 was innocent towards any cations or anions. The LOD for A5R1 with Cu2+ was found to be 2.63 ppm. A5R2 detected PO43¯ and CO32¯ with limit of detections 4.13 ppm and 5.40 ppm respectively. The interference studies indicated that there was no other ion which could restrain the analysis. Job’s Plots showcased the 1:2 binding of the receptors with the analyte ion(s). The practical applicability of the probes was demonstrated by on-field detection kit and test-strip fabrication with colour change chart. Logic gate formulation with active simulation governed by the reversibility studies envisaged the reversibility and reusability of the probe and its solicitation in making electric devices. Furthermore, spiking studies proved the application of the receptors for convenient analyte detection in real-life food and water samples.

Application of modified Sargassum dupilcatum biomass as an eco-friendly adsorbent for removing coomassie brilliant blue and phosphate ions from solution

Application of modified Sargassum dupilcatum biomass as an eco-friendly adsorbent for removing coomassie brilliant blue and phosphate ions from solution

Исследование закономерностей изменения солевого состава буровых шламов в процессе их утилизации

Drill cuttings in their natural state have viscous-plastic properties; in a dry state they are cohesive and hard. This is due to the content of sodium ions in the absorbing complex. Features of the physical and mechanical properties of drill cuttings indicate its ability to absorb and retain dissolved salts. When gypsum is added to drill cuttings in different percentages of the waste volume, the concentration of chloride ion changes in all samples, and chloride-sulfate salinization is observed. The content of sulfate ion increases with a minimum volume fraction of gypsum application. The addition of gypsum in a volume fraction of 15 and 20% affects the reduction of phosphate and carbonate ions. A change in electrical conductivity indicates an increase in the concentration of water-soluble salts in the water extract, which is confirmed by a direct high correlation. When adding gypsum from 7–20% volume fractions, a significant reduction in the dense residue occurs. The use of gypsum increases the filtration capacity of drill cuttings. The use of gypsum makes it possible to lighten the granulometric composition of drill cuttings due to the active coagulation of colloids. As a result of the removal of water-soluble salts, optimal water-physical properties of drill cuttings are created, structuring and filtration properties of drill cuttings are increased. A mathematical model for predicting the dissolution of salts in drill cuttings allows taking into account uncontrollable factors (density, particle size distribution, filtration coefficient, content of water-soluble salts).

Correlating Material Properties to Osteoprotegerin Expression on Nanoparticulate Mineralized Collagen Glycosaminoglycan Scaffolds.

Precision material design directed by cell biological processes represents a frontier in developing clinically translatable regenerative technologies. While understanding cell-material interactions on multipotent progenitor cells yields insights on target tissue differentiation, equally if not more important is the quantification of indirect multicellular interactions. In this work, the relationship of two material properties, phosphate content and stiffness, of a nanoparticulate mineralized collagen glycosaminoglycan scaffold (MC-GAG) in the expression of an endogenous anti-osteoclastogenic secreted protein, osteoprotegerin (OPG) by primary human mesenchymal stem cells (hMSCs) is evaluated. The phosphate content of MC-GAG requires the type III sodium phosphate symporter PiT-1/SLC20A1 for OPG expression, correlating with β-catenin downregulation, but is independent of the effects of phosphate ion on osteogenic differentiation. Using three stiffness MC-GAG variants that do not differ significantly by osteogenic differentiation, it is observed that the softest material elicited ≈1.6-2 times higher OPG expression than the stiffer materials. Knockdown of the mechanosensitive signaling axis of YAP, TAZ, β-catenin and combinations thereof in hMSCs on MC-GAG demonstrates that β-catenin downregulation increases OPG expression by 1.5-fold. Taken together, these data constitute a roadmap for material properties that can used to suppress osteoclast activation via osteoprotegerin expression separately from the anabolic processes of osteogenesis.

Self-Organization of Polyurethane Ionomers Based on Organophosphorus-Branched Polyols.

Based on organophosphorus branched polyols (AEPAs) synthesized using triethanolamine (TEOA), ortho-phosphoric acid (OPA), and polyoxyethylene glycol with MW = 400 (PEG), vapor-permeable polyurethane ionomers (AEPA-PEG-PUs) were obtained. During the synthesis of AEPAs, the reaction of the OPA etherification with polyoxyethylene glycol was studied in a wide temperature range and at different molar ratios of the starting components. It turned out that OPA simultaneously undergoes a catalytically activated etherification reaction with triethanolamine and PEG. After TEOA is fully involved in the etherification reaction, excess OPA does not react with the terminal hydroxyl groups of AEPA-PEG or the remaining amount of PEG. The ortho-phosphoric acid remaining in an unreacted state is involved in associative interactions with the phosphate ions of the AEPA. Increasing the synthesis temperature from 40 °C to 110 °C leads to an increase in OPA conversion. However, for the AEPA-PEG-PU based on AEPA-PEG obtained at 100 °C and 110 °C, ortho-phosphoric acid no longer enters into associative interactions with the phosphate ions of the AEPA. Due to the hydrophilicity of polyoxyethylene glycol, the presence of phosphate ions in the polyurethane structure, and their associative binding with the unreacted ortho-phosphoric acid, the diffusion of water molecules in polyurethanes is enhanced, and high values of vapor permeability and tensile strength were achieved.

Enhancement of Calcium Chelating Activity in Peptides from Sea Cucumber Ovum through Phosphorylation Modification.

Recently, phosphorylation has been applied to peptides to enhance their physiological activity, taking advantage of its modification benefits and the extensive study of functional peptides. In this study, water-soluble peptides (WSPs) of sea cucumber ovum were phosphorylated in order to improve the latter's calcium binding capacity and calcium absorption. Enzymatic hydrolysis methods were screened via ultraviolet-visible absorption spectroscopy (UV-Vis), the fluorescence spectrum, and calcium chelating ability. Phosphorylated water-soluble peptides (P-WSPs) were characterized via high-performance liquid chromatography, the circular dichroism spectrum, Fourier transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, surface hydrophobicity, and fluorescence spectroscopy. The phosphorus content, calcium chelation rate and absorption rate were investigated. The results demonstrated that phosphorylation enhanced the calcium chelating capacity of WSPs, with the highest capacity reaching 0.96 mmol/L. Phosphate ions caused esterification events, and the carboxyl, amino, and phosphate groups of WSPs and P-WSPs interacted with calcium ions to form these bonds. Calcium-chelated phosphorylated water-soluble peptides (P-WSPs-Ca) demonstrated outstanding stability (calcium retention rates > 80%) in gastrointestinal processes. Our study indicates that these chelates have significant potential to develop into calcium supplements with superior efficacy, bioactivity, and stability.

The formation, stability and microstructure of calcium phosphate nanoclusters sequestered by casein phosphopeptides

Casein phosphopeptides have been hypothesized to be responsible for stabilizing supersaturated calcium and phosphate ions through the formation of complexes, making them biologically available for intestinal absorption. Considering the importance of phosphopeptides on calcium phosphate salts, this study focused on the formation and stability of calcium phosphate nanocluster (CPN) complexes sequestered by casein phosphopeptides with different concentrations. The complexes formed with phosphopeptides of 2.5 mg/mL were large particles with an uneven size distribution. With addition of 5–7.5 mg/mL phosphopeptides, the complexes formed reached a uniform nano-scaled size after equilibrium, but these nanoclusters gradually aggregated with each other resulting in large particles formed during storage. In contrast, the change of CPN complexes formed with 10 mg/mL phosphopeptides in average particle size was not significant (p < 0.05) with time, showing a good stability. Based on salt analyses and ion activity product (IAP) calculation as a function of pH, the calcium phosphate within nanoclusters was found to be a neutral salt with a chemical formula of Ca(HPO4)0.4(PO4)0.4 and an invariant ion activity product of 8.00 ± 0.03. Small angel x-ray scattering (SAXS) and cryo-TEM were used for microstructural characterization, revealing that most of CPN complexes were of core-shell sphere structure with a core of amorphous calcium phosphate. Besides, the surface of CPN complexes was expected to be rough rather than smooth, and these nanocluster complexes are likely to be of both kinetic stability and relatively thermodynamic stability.

Changes in the enamel surface in patients with polymorphism of the &lt;i&gt;VDR&lt;/i&gt; gene under the action of remineralizing composition and vitamin D

BACKGROUND: The leading role in the pathogenetic mechanism of caries development is the imbalance between the de and remineralization of hard tooth tissues. The combination of VDR alleles affects calcium-phosphate metabolism. In 65% of the human population, the structure of the VDR gene has a genetic polymorphism. AIM: To study the effect of vitamin D and a remineralizing paste on the enamel surface structure in patients with genetic polymorphism of VDR gene receptors. MATERIALS AND METHODS: In 18 individuals with a polymorphism index of the VDR A/A gene, a laboratory indicator of 25 (OH) vitamin D in the blood of 18.20±1.84 ng/ml, according to orthodontic indications, the retinated third molars in the lower jaw were removed. Then, the samples were lowered into three flasks of six pieces with 100 ml of artificial saliva. Containers with teeth were divided into groups: group 1, with a solution of artificial saliva only; group 2, an additional 1,000 IU of an aqueous solution of vitamin D; and group 3, tooth enamel was treated for 2 minutes with an electric toothbrush with a paste containing a remineralizing composition, immersed in artificial saliva with cholecalciferol 1,000 IU. The flasks were in the thermostat at a temperature of 37.4 C per day. In all samples, electron microscopy of the enamel contact surface at the level of the crown equator was performed using a Tescan Mira 3 LMU microscope (TESCAN, Czech Republic) with an Oxford X-MAX 5 energy dispersive X-ray detector (Oxford Instruments, United Kingdom) with analysis of local mineral composition. RESULTS: In group 1, with electron microscopy of enamel, areas of increased mineralization alternated with areas of reduced density. The coefficient of the molar ratio Ca/P was 1.32±0.13, indicating the destruction of hydroxyapatites. In group 2 the intercrystalline pore space was filled with calcium and phosphate ions. In group 3, the enamel surface acquired a smooth homogeneous relief. An increase in the weight percentage of trace elements was observed, and the Ca/P ratio was 2.20±0.02, which indicated a phase of remineralization. CONCLUSION: Patients with VDR gene polymorphism have a vitamin D deficiency in the blood serum. The trace element composition of the enamel surface is characterized by a phase of demineralization. Treatment with remineralizing paste and addition of cholecalciferol solution to artificial saliva changes the structure of hydroxyapatite and increases the caries-resistant properties of enamel.

Removal of metals and emergent contaminants from liquid digestates in constructed wetlands for agricultural reuse.

Given the increasing pressure on water bodies, it is imperative to explore sustainable methodologies for wastewater treatment and reuse. The simultaneous presence of multiples contaminants in complex wastewater, such as the liquid effluents from biogas plants, can compromise biological treatment effectiveness for reclaiming water. Vertical subsurface flow constructed wetlands were established as low-cost decentralized wastewater treatment technologies to treat the liquid fraction of digestate from municipal organic waste with metals, antibiotics, and antibiotic resistance genes, to allow its reuse in irrigation. Twelve lab-scale planted constructed wetlands were assembled with gravel, light expanded clay aggregate and sand, testing four different treating conditions (liquid digestate spiked with oxytetracycline, sulfadiazine, or ofloxacin, at 100 μg/ L, or without dosing) during 3 months. Physicochemical parameters (pH, chemical oxygen demand (COD), nutrients, metals, and antibiotics), the microbial communities dynamics (through 16S high-throughput sequencing) and antibiotic resistance genes removal (qPCR) were monitored in influents and effluents. Systems removed 85.8%-96.9% of organic matter (as COD), over 98.1% of ammonium and phosphate ions, and 69.3%-99.4% of nitrate and nitrite ions, with no significant differences between the presence or absence of antibiotics. Removal of Fe, Mn, Zn, Cu, Pb and Cr exceeded 82% in all treatment cycles. The treatment also removed oxytetracycline, sulfadiazine and ofloxacin over 99%, and decreased intl1, tetA, tetW, sul1 and qnrS gene copies. Nonetheless, after 3 months of ofloxacin dosing, qnrS gene started being detected. Removal processes relied on high HRT (14 days) and various mechanisms including sorption, biodegradation, and precipitation. Microbial community diversity in liquid digestate changed significantly after treatment in constructed wetlands with a decrease in the initial Firmicutes dominance, but with no clear effect of antibiotics on the microbial community structure. Removals above 85% and 94% were observed for Streptococcus and Clostridium, respectively. Results suggest that vertical subsurface flow constructed wetlands were a suitable technology for treating the liquid digestate to reuse it in irrigation agricultural systems, contributing to the circular bioeconomy concept. However, a more profound understanding of effective wastewater treatment strategies is needed to avoid antibiotic resistance genes dissemination.

The Influence of Phosphate Ion Concentrations on the Properties of Wollastonite-Apatite-Based Cements

The Influence of Phosphate Ion Concentrations on the Properties of Wollastonite-Apatite-Based Cements

Phosphorus: Chronicles of the epistemology of a vital element.

It was in the philosopher's stone quest that the alchemist Hennig Brand isolated chemiluminescent white phosphorus (P), Greek for "light bearer", from urine in 1669. By 1771 phosphorus was isolated from bone, and in 1777 it was identified by Antoine Lavoisier as a highly reactive element that exists predominantly in nature as ionic phosphate (PO43-) and in solution as phosphoric acid (H3PO4). Early 20th century studies revealed phosphorylated biomolecules as essential components of replicative nuclear material (RNA, DNA), a metabolic source of energy (ATP), and structural components of cellular membrane (phospholipid bilayer). Life on earth began as organophosphates of a self-replicating RNA that evolved into DNA and acquired a membrane to form the original eukaryotes, which eventually joined to form multicellular organisms of the deep sea. Tissue mineralization during transition from the ocean to land generated the endoskeleton, the largest phosphorus stores of evolving vertebrates. Subsequent studies of phosphate homeostasis elucidated its complex regulatory system based on the interaction of the kidney, small intestine, bone, and parathyroid glands, orchestrated by hormones (PTH, calcitriol, FGF23, Klotho), and carried out by phosphate-specific transporters (SLC34 and SLC20 families) all to ensure adequate phosphate for survival and health. Paradoxically, kidney replacement therapy in the 1970s, by prolonging the lives of millions of individuals with kidney failure, revealed the hazards of phosphorus excess. "Phosphorus the light bearer" has become in the eyes of many nephrologists "Phosphorus the cardiovascular toxin".

Synthesis of graphene oxide-choline chloride in order to remove phosphate ion from aqueous samples: study of mechanism, isotherm and adsorption kinetics

In this study, a graphene oxide-choline chloride adsorbent was used as a highly efficient and environmentally friendly material for removing phosphate ions from aqueous samples. Graphene oxide was synthesized using the Hummers method and then modified with choline chloride to create the graphene oxide-choline chloride adsorbent. The synthesized adsorbent was characterized using Fourier transform infrared spectrophotometry (FT-IR), Field Effect Scanning Electron Microscopy (FESEM), and Energy-dispersive X-ray spectroscopy (EDX). It was then applied to remove phosphate ions at different pH levels and stirring times. The results of this study showed that the maximum removal efficiency of phosphate ions was achieved at pH 5, with an adsorbent amount of 0.015 g and a stirring time of 30 minutes. Furthermore, it was observed that the adsorption of phosphate ions on the adsorbent surface followed the Langmuir isotherm (monolayer adsorption), with a maximum adsorption capacity of 217.4 mg/g. The examination of absorption kinetics also revealed that the absorption of phosphate ions followed pseudo-second-order kinetics, and an increase in temperature favored the progress of the reaction.

Alendronate as Bioactive Coating on Titanium Surfaces: An Investigation of CaP-Alendronate Interactions.

The surface modification of dental implants plays an important role in establishing a successful interaction of the implant with the surrounding tissue, as the bioactivity and osseointegration properties are strongly dependent on the physicochemical properties of the implant surface. A surface coating with bioactive molecules that stimulate the formation of a mineral calcium phosphate (CaP) layer has a positive effect on the bone bonding process, as biomineralization is crucial for improving the osseointegration process and rapid bone ingrowth. In this work, the spontaneous deposition of calcium phosphate on the titanium surface covered with chemically stable and covalently bound alendronate molecules was investigated using an integrated experimental and theoretical approach. The initial nucleation of CaP was investigated using quantum chemical calculations at the density functional theory (DFT) level. Negative Gibbs free energies show a spontaneous nucleation of CaP on the biomolecule-covered titanium oxide surface. The deposition of calcium and phosphate ions on the alendronate-modified titanium oxide surface is governed by Ca2+-phosphonate (-PO3H) interactions and supported by hydrogen bonding between the phosphate group of CaP and the amino group of the alendronate molecule. The morphological and structural properties of CaP deposit were investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and attenuated total reflectance Fourier transform infrared spectroscopy. This integrated experimental-theoretical study highlights the spontaneous formation of CaP on the alendronate-coated titanium surface, confirming the bioactivity ability of the alendronate coating. The results provide valuable guidance for the promising forthcoming advancements in the development of biomaterials and surface modification of dental implants.